Quaternary ammonium salts in silver halide processing solutions



United States Patent Office 3,314,789 Patented Apr. 18, 1967 This invention relates to photographic processing solutions and in particular to improved solutions containing specific onium salts.

The use of onium compounds in photographic emulsions and in photographic processing solutions has been extensively investigated by those skilled in the art. For instance, T. H. James has discussed the effects of quaternary ammonium salts in the Journal of Physical Chemistry, volume 43, page 701 (1939). These compounds have been helpful in controlling the sensitometric results of images obtained p-hotographically. In particular, it has been noted that they have some control over image tone, fog level, speed and contrast and granularity. However, many of these compounds have been noted for their instability when incorporated in processing solu- For instance, it was necessary to use the processing solution such as a developer within a relatively short period after the onium compound was incorporated therein. This has seriously restricted the usefulness of developer solutions having onium compounds therein,

particularly the use of specific onium compounds which were useful in reducing the fog level and improving the granularity. Accordingly, it has been desirable to find compounds which could be used in developer solutions which would have good keeping qualities over a relatively long period of time.

In the diffusion transfer field, it has been recognized that toners are desirable in order to obtain a neutral tone in the positive print. The use of onium'salts in the diffusion transfer type developers has also been desirable. Certain of the onium compounds such as quaternary ammonium salts, have a linear chain of at least 7 atoms attached directly to a quaternary nitrogen atom, have been found useful when used with certain organic sulfurand nitrogen-containing compounds as disclosed in U.S. Patent 3,017,270, issued Jan. 16, 1962, to Tregillus and Rasch. However, these onium compounds were also of limited stability when incorporated in the developer solution over a period of time. They have also been limited in their use in the typical chemical developing types of silver halide emulsion.

In one particular adaptation of the diffusion transfer system, a web is employed which contains centers for physical development and is imbibed with a developer solution. After the light sensitive silver halide emulsion has been exposed, it is contacted against the web and the developer solution acts to facilitate the formation of a positive image on the web, at the same time developing a negative image in the silver halide emulsion. In this system, it is often desirable to obtain a satisfactory nega: tive image as well as a positive image, so that the developer formulation needs to be prepared differently from the developers which. are used when only a positive image is desired in the diffusion transfer process and the negative is discarded after having been used to form the positive image. This also requires conditions different from those required when ,a negative image only is to be made by the process. For these reasons, it is desirable to have components in the developer which will reduce granularity this respect, the requirements differ considerably from a typical diffusion transfer type developer, wherein fog or grain size in the negative are of relatively little importance.

in the negative image. In

which will reduce fog and It hasalsobeen desirable, When using pounds which are stable in processing solutions, especially those used for diffusion transfer purposes, but which will have an effect on the developed silver halide emulsion of reducing fog level and reducing grain size, but which will provide good contrast as well as satisfactory speed.

We have found certain novel quaternary ammonium salts which can be incorporated in processing formulations with improved results in both chemical and physical development processes.

One object of this invention is to provide onium compounds useful in developer compositions which reduce fog level, particularly under high temperature processing conditions. Another object is to provide contrast and speed control in developing silver halide emulsions. A further object is to provide a method of obtaining increased D of positive diffusion transfer images. A still further object is to provide a method of obtaining reduction in negative granularity. Another object is to improve the stability of silver halide processing solutions. Additional objects will be apparent from the following disclosure. I

The above objects are obtained by incorporating quaternary ammonium salts represented by the general formula:

where Y is an alkyl thio group of 6-30 carbon atoms or a secondary or a tertiary amino group containing alinear chain of 'l030 carbon atoms, R represents lower alkyl groups of 1-4 carbon atoms, and X is a suitable anionsuch as p-toluene-sulfonate, perchlorate, chloride, bromide, sulfate, phosphate, methylsulfate or the like. These, compounds are prepared by reacting a quaternary ammonium epoxide with an appropriate amine or mercaptan as described in Burness U.S. Patent 3,246,669. A useful range of the onium compounds in a developer solution is 25- 2000 milligrams per liter. Film-like materials containing a swellable layer into which solution may be imbibed, may be presoaked in imbibant to the extent of 6-9 milliliters per square foot.

In a particularly useful. embodiment of this invention, the onium compound can be used in a diffusion transfer process in conjunction with a tone modifier. Certain tone modifiers are particularly effective in showing a synergistic effect in the reduction of negative fog and increase in speed and contrast. Among the tone modifiers which are useful in this regard are:

3,4-di-a1nino-5 -mercapto- 1 ,2,4-triazole, 4-phenyl-5-imino-thiourazole, 5-ethyl-3-mercapto-4phenyl-1,2,4-triazole, and 4-phenyl-di-thi0urazole.

Certain other tone modifiers which may be incorporated but which do not result in a synergistic effect of the onium compounds of our invention are as follows:

It will be appreciated that our onium compounds can be used in customary silver halide photographic solutions including those employing hydroquinone and its derivatives, N-methyl-p-aminophenol sulfate, pyrazolidone derivatives and the like, and may also be used in developers containing a silver halide solvent such as those intended for diffusion transfer and for monobaths which contain a fixing agent.

Typical silver halide emulsions may be used including light sensitive silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver bromoiodide and silver chlorobromoiodide. Binders customarily used for silver halide emulsions may be used as well as supports which are known in the art. When used in diffusion transfer, the solution may be used in a web type process by imbibing into a hydrophilic web of the type described in Tregillus et al. US. Patent 3,179,517, which issued Apr. 20, 1965, or in a viscous solution of the type used in pod processing. The supports used for the silver halide emulsion are not critical and may be any of those known in the art. When our invention is used in the diffusion transfer process, typical nucleating agents such as Carey Lea silver, heavy metal salts and the like may be used on the receiving support. The support may be paper or film base such as cellulose ester, organic polymeric materials or the like.

In those cases 'where the diffusion transfer process involves the development of dye images by means of the paraphenylenediamine type developing agents, suitable colored or colorless coupler compounds of the phenolic, hydroxyl, pyrazolone and open chain reactive methylene types may be employed in the emulsion, receiving sheet or developer. Our developed compounds are similarly beneficial for use with other types of diffusion transfer processes, such as those wherein a unitary element is provided having, for example, a removable cellulose ether phthalate silver halide emulsion layer coated upon a receiving layer containing a silver precipitant. The element is exposed in a suitable manner, development initiated in the presence of a silver halide solvent and the onium compound, and a positive image formed in the receiving layer accompanied by removal of the overlying emulsion layer containing the negative image.

The following tables indicate particularly useful specific compounds in our invention.

TABLE I.-QUATERNARY AMMONIUM COM- POUNDS WITH THIOETHER LINKAGE TO THE ALKYL GROUP TABLE II.--QUATERNARY AMMONIUM COM- POUNDS WITH SECONDARY AMINE LINKAGE TO THE ALKYL GROUP R=C5H13 s r1 io 21 12 25 1e a3 The following examples are intended to illustrate our invention but not to limit it in any way.

Example 1 A diffusion transfer developer was prepared containing: Z-methylaminoethanol-SO addition product, 19.9%

S0 by weight ml 90.0 Hydroquinone g 5.0 Sodium thiosulfate, pentahydrate g 20.0 4-4 dimethyl 1 phenyl 3 pyrazolidone g 0.5 4 phenyl 3 imino -thiourazole g 0.1 (2 hydroxy 4 thiatetradecyl) trimethyl ammonium p-toluene sulfonate g 0.4

Water to make 1.0 liter.

The above solution was imbibed into a processing web which consisted of a gelatin coating containing 2000 mg./ .ft. of gelatin on a polyester support. The gelatin layer contained nickel sulfide nuclei dispersed uniformly throughout the layer. The web was soaked for 3 minutes at until the web contained about 6 grams solution per square foot. It was then rolled into contact with a moderately high speed aerial negative film for one minute at F. The negative was then further fixed by contacting with a fresh web made in an identical manner. The sensitometric characteristics are tabulated below. W

Fog Gamma The data show both reduction in fog and an increase in speed and contrast.

Example 2 In the quaternary compounds, alkyl groups varying from six to sixteen C atoms as shown in Tables I and II above, were substituted for the C alkyl group of the (2 hydroxy 4 thiatetradecyl) trimethyl ammonium p-toluene sulfonate of Example 1. Processing was carried out as in Example 1 and the minimum densities and sensitometric values obtained from such experiments are given below.

Negative Chain length Concen., Minimum Compounds of (No. of C atoms) g./l. Density Gamma Speed,

A Log E Table I 0 37 1. 47 00 1. 0 37 1. 43 00 1. 0 12 1. 65 18 0. 4 13 1. 57 16 1. 0 18 1. 40 00 1. 0 40 1. 32 00 Table II 1. 0 37 1. 40 00 1. 0 38 1. 36 00 1. 0 16 l. 47 16 1. 0 16 1. 48 18 1. 0 34 1. 49 05 Example 3 The preferred quaternary salts of our invention show good stability in processing solutions as indicated by the following examples.

A diffusion transfer developer was prepared containmg:

2-methylaminoethanol-SO addition product, 19.9%

S by weight ml 90.0 Hydroquinone g 5.0

Sodium thiosulfate, pentahydrate g 20.0 4,4 dimethyl 1 phenyl 3 pyrazolidone g 0.5 4 phenyl 3 imino thiourazole ag 0.1 Dodecyl dirnethyl sulfonium p toluene sulfonate g 0.2

Water to make 1.0 liter.

left in contact at 90 F. for one minute. They were then separated and another piece of soaked receiver was pressed in contact with the negative to complete the processing.

The data below show the results on the sensitometric properties of the solutions incubated before use.

Concen.

Solution Fog was replaced with Example 4 A medium speed silver br-omoiodide emulsion was processed in D-76 developer containing 40 mg./liter of (2 hydroxy 4 thiatetradecyl) trimethyl ammonium p-toluene sulfonate. Time of development was eight minuates at 68 F. with nitrogen burst agitation (1 cycle/ 10 seconds at 5 psi). Controls were processed in D-76 developer in the same manner. The following results were obtained:

Sensitometry Negative Granularity Resolving arnma Power 1 E M a a Kodak D-76 1. 39 0.052 112 Modified D76 1.27 0. 047 140 1 Resolving power was measured using a 1000zl Chart Contrast.

From the above data and the picture evaluation, was evidenced a considerable gain in image structure with the modified D-76.

Example 5 A low-negative gamma (1.01.2) process using a medium speed silver bromoiodide emulsion and a processing web similar to that used in Example 1 was soaked for three minutes at 117 F. in the following developer:

G. Methylaminoethanol-SO (20.3% S0 18.0 4-metl1yl-1-phenyl-3-pyrazolidone 0.2 Hydroquinone 1.5 Potassium iodide .04 Sodium thiosulfate, anhyd. 2.5 2 hydroxy 4 thiatet-radecyl trimethyl ammonium p toluene sulfonate .02 Water to make 100.0 ml. The results were as follows: Sensitometry: Negative gamma 1.14 Granularity: 24 X Web process 0.040 8 minutes, D19 0 084 Chart Contrast Resolving Power:

eb process, negative minutes, D-19 Picture evaluation: The web process was superior in image structure as compared to an 8-minute D-76 control.

Example 6 A D-76 developer solution having the following components was prepared:

G. p-methylaminophenol 2.0 Sodium sulfite des. 100.0 Hydroquinone 5.0 Borax 2.0

Sensitometric strips and photographic exposures of an aeria They were fixed, washed and dried in the normal manner. These strips were controls for the samples developed in the following way:

A second set (B) of strips and exposures were developed in the developer solution used for the controls to which 50 rug/liter of dimethyldodecyl sulfonium p-tolu- Development for 6 minutes at 68 F. produced sensitometric curves which had equal contrast to the control negatives, since onium salts act as development accelerators. The strips were fixed, washed and dried as above.

To a third portion of the developer solution 40 mg./ liter of (2ehydroxy-4-thiatetradecyl) trimethylammonium p-toluene sulfonate was added and strips (C) were developed for 8 minutes at 68 F. The contrast of the sensitometric strips matched that of the control.

of the negative processed all three processing conditions to produce the same-photographic speed.

The negatives were inter-comparison microscope at about 30X magnification. Strip B showed more graininess than the control and strip C showed less graininess than the control. The fine detail image material of'the aerial scenes was more clearly defined in the C strip process than in either of the other two.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

It will be appreciated that our developing solution may contain more than one onium compound, each imparting its own attributes independent of the others.

We claim:

1. In a diffusion transfer system wherein a silver halide emulsion layer containing a latent photographic image is contacted in super-posed relation with a waterpermeable hydrophilic organic colloid processing element separable from said emulsion layer and having dispersed therein a silver precipitating agent, said processing element containing an amount of processing solution sufficient to develop said exposed silver halide to metallic silver and to dissolve substantially all undeveloped silver halide from said exposed emulsion layer, the improvement comprising using a processing solution containing at least one (a) silver halide developing agent and (b) silver halide fixing agent with (c) a quaternary ammonium salt represented by the general formula:

where Y is selected from the class consisting of an alkyl thio group of 63() carbon atoms, a secondary amino group containing a linear chain of 10-30 carbon atoms and a tertiary amino group containing a linear chain of 1030 carbon atoms, R represents lower alkyl groups of 1-4 carbon atoms and X is a suitable anion.

2. A process of claim 1 in which the processing solution contains a tone modifier.

3. A process of claim 1 in which the processing solution contains a tone modifier selected from the class consisting of 3,4-di-amino--mercapto-1,2,4-triazole, 4- phenyl 5 imine thiourazole, 5 ethyl 3 mercapto- 4 phenyl 1,2,4 triazole and 4 phenyl-di-thiourazole.

4. A process of claim 1 in which the processing solution contains 25-2000 mg. per liter of the quaternary ammonium salt.

5. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-thiadecyl)tri-alkyl ammonium p-toluene sulfonate.

6. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-thiadodecyl)tri-alkyl ammonium p-toluene sulfonate.

7. A' process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-thiatetradecyl)tri-alkyl ammonium p-toulene sulfonate.

8. A process of claim 1 in which the quaternary amammonium salt is a (2-hydroxy-4-thiahexadecyl)tri-alkyl ammonium p-toluene sulfonate.

9. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-thiaeicosyl)tri-alkyl ammonium p-toluene sulfonate.

10. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-aminodecyl)tr-i-alkyl ammonium p-tol uene sulfonate.

11. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-aminododecyl)tri-alkyl :ammonium p-toluene sulfonate.

12. A process of claim 1 in which the quaternary am- :monium salt is a (2-hydroxy-4-aminotetradecyl)tri-alkyl ammonium p-toluene sulfonate.

13. A process of claim 1 in which the quaternary ammonium salt is a (2-hydroxy-4-aminohexadecyl)tri-alkyl ammonium p-toluene sulfonate.

14. A process of claim. 1 in which the quaternary ammonium salt is a (2-hydroxy-4-arninoeicosyl)tri-alkylammonium p-toluene sulfonate.

15. In a diffusion transfer system wherein a silver halide emulsion layer containing a latent photographic image is contacted in superposed relation with a Waterpermeable hydrophilic organic colloid processing element separable from said emulsion layer and having dispersed therein a silver precipitating agent, said processing element containing an amount of processing solution sufficient to develop said exposed silver halide to metallic silver and to dissolve substantially all undeveloped silver halide from said exposed emulsion layer, said processing solution containing at least one (a) silver halide developing agent and (b) silver hadie fixing agent, the improvement comprising imbibing into said processing element a quaternary ammonium salt represented by the general formula:

where Y is selected from the class consisting of an alkyl thio group of 6-30 carbon atoms, a secondary amino group contining a linear chain of 10-30 carbon atoms and a tertiary amino roup containing a linear chain of 10-30 carbon atoms, R represents lower alkyl groups of l4 carbon atoms and X is a suitable anion.

16. A process of claim 15 in which the processing solution contains a tone modifier.

17. A process of claim 15 in which the processing solution contains a tone modifier selected from the class consisting of 3,4 di amino 5 mercapto 1,2,4 triazole, 4 phenyl 5 imine thiourazole, S ethyl 3- mercapto 4 phenyl 1,2,4 triazole and 4 phenyl dithiourazole.

18. A process of claim 15 in which the processing solution contains 25200() mg. per liter of the quaternary am monium salt.

19. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-thiadecyl)tri-alkyl ammonium p-toluene sulfonate.

20. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-thiadodecyl)tr-i-alkyl ammonium p-toluene sulfonate.

21. A process of claim 15 in which the quaternary ammonium salt is a 2-hydroxy-4-thiatetradecyl)tri-alkyl ammonium p-toluene sulfonate.

22. A process of claim 15 in which the quaternary am monium salt is a (2-hydroxy-4-thiahexadecyl)tri-alkyl ammonium p-toluene sulfonate.

23. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-thiaeicosyl)tri-alkyl ammonium p-toluene sulfonate.

24. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy4-aminodecyl)tri-alkyl ammonium p-toluene sulfonate.

25. A process of claim 15 in which the quaternary ammonium salt is a (2hydroxy-4-aminododecyl)tri-alkyl ammonium p-toluene sulfonate.

26. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-aminotetradecyl)tri-alkyl ammonium p-toluene sulfonate.

27. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-aminohexadecyl)tri-alkyl ammonium p-toluene sulfonate. Y

28. A process of claim 15 in which the quaternary ammonium salt is a (2-hydroxy-4-aminoeicosyl)tri-alkyl ammonium p'toluene sulfonate.

References Cited by the Examiner UNITED STATES PATENTS NORMAN G. TORCHIN, Primary Examiner. J. TRAVIS BROWN, Examiner. C. E. DAVIS, Assistant Examiner. 

1. IN A DIFFUSION TRANSFER SYSTEM WHEREIN A SILVER HALIDE EMULSION LAYER CONTAINING A LATENT PHOTOGRAPHIC IMAGE IS CONTACTED IN SUPERPOSED RELATION WITH A WATER-PERMEABLE HYDROPHILIC ORGANIC COLLOID PROCESSING ELEMENT SEPARABLE FROM SAID EMULSION LAYER AND HAVING DISPERSED THEREIN A SILVER PRECIPITATING AGENT, SAID PROCESSING ELEMENT CONTAINING AN AMOUNT OF PROCESSING SOLUTION SUFFICIENT TO DEVELOP SAID EXPOSED SILVER HALIDE TO METALLIC SILVER AND TO DISSOLVE SUBSTANTIALLY ALL UNDEVELOPED SILVER HALIDE FROM SAID EXPOSED EMULSION LAYER, THE IMPROVEMENT COMPRISING USING A PROCESSING SOLUTION CONTAINING AT LEASE ONE (A) SILVER HALIDE DEVELOPING AGENT AND (B) SILVER HALIDE FIXING AGENT WITH (C) A QUATERNARY AMMONIUM SALT REPRESENTED BY THE GENERAL FORMULA: 